Effect of planting time and growth regulators on growth and seed quality parameters of larkspar (Delphinium ajacus L.)

Investigations were undertaken to standardize the planting time of Delphinium ajacus L using five planting dates viz., 20^th October, 5th November, 20^th November, 5^th December and 20^th December. Maximum seed yield (14.41g/m²) was obtained when planting was carried out on 20th October, which decreased as the planting was delayed beyond 5^th November. The high seed yield was attributed to better plant growth in terms of plant height (92.67 cm), plant spread (40.49 cm) and branches (14.86/plant) from early planting. In another experiment, seed germination was determined using different concentrations of thiourea, benzyl adenine, kinetin, potassium nitrate, boric acid, gibberellic acid and ethrel. The maximum seed germination (96.67%) was recorded with 10 ppm gibberellic acid as compared to control where seed germination was 83.00% in the month of June. The seed treatment with 50 ppm kinetin gave highest germination (90.33%), followed by 25 ppm gibberellic acid (88.00%) in the month of September.